I wandered into the preserve from St. Edwards and did not see any signs for the need of a permit...Hmm? I should have actually read the sign. Makes sense, I guess. As a passive user sticking to the trail, you might be able to talk your way out of any citation if you bump into City personnel. Seeing that Feb-Jun is the breeding season for the golden-cheeked warbler, it's probably not a good idea to get caught in the preserve without the proper authorization during those months.